All Black injury crisis deepens

New Zealand suffered a triple blow ahead of their return match against Australia in Wellington on Saturday.

All Black pivot Aaron Cruden and his back-up Beauden Barrett have both been ruled out of the Rugby Championship Round Two clash.

Lock Luke Romano has also been sidelined with a groin injury. He tore his right adductor tendon, the Kiwis said in a medical dispatch on Tuesday.

The trio were all injured in New Zealand's 47-29 win over the Wallabies in Sydney last Saturday, adding to an All Blacks' sick list that already includes first-choice flyhalf Dan Carter and forward Liam Messam.

Coach Steve Hansen said Romano was set to miss the entire tournament and would not be available until New Zealand's European tour in November.

Cruden would be out for anywhere from two-to-six weeks with a posterior cruciate ligament knee injury.

"It's obviously hugely disappointing for Luke but he is a strong character and is already planning his rehab with our medical staff," Hansen said.

He said Barrett had a minor calf strain and should only miss two Tests.

"We hopefully will have Beauden ready to prepare for the Argentina Test [in Hamilton on September 7], while Aaron will start his knee rehabilitation later this week - which will give us a better indication of when he will be back playing."

New Zealand had already prepared for the worst, calling up pivots Colin Slade and Tom Taylor, along with forwards Luke Whitelock and Brad Shields to cover any injuries for the game in Wellington.

"It's an exciting time for the replacement players Tom Taylor and Colin Slade and it's also a challenge now for the rest of the team to make their entry into the side as seamless as possible," Hansen said.

Injury-prone Slade, 25, has played 10 Tests and will be favourite to start against the Wallabies ahead of the uncapped Taylor.